AIM:To evaluate corneal astigmatic outcomes of femtosecond laser-assisted arcuate keratotomies(FAKs)combined with femtosecond-laser assisted cataract surgery(FLACS)over 12mo follow-up.METHODS:Totally 145 patients with...AIM:To evaluate corneal astigmatic outcomes of femtosecond laser-assisted arcuate keratotomies(FAKs)combined with femtosecond-laser assisted cataract surgery(FLACS)over 12mo follow-up.METHODS:Totally 145 patients with bilateral cataracts and no ocular co-morbidities were recruited to a singlecentre,single-masked,prospective randomized controlled trial(RCT)comparing two monofocal hydrophobic acrylic intraocular lenses.Eyes with corneal astigmatism(CA)of>0.8 dioptres(D)received unpaired,unopened,surface penetrating FAKs at the time of FLACS.Visual acuity,subjective refraction and Scheimpflug tomography were recorded at 1,6,and 12mo.Alpins vectoral analyses were performed.RESULTS:Fifty-one patients(61 eyes),mean age 68.2±9.6y[standard deviation(SD)],received FAKs.Sixty eyes were available for analysis,except at 12mo when 59 attended.There were no complications due to FAKs.Mean pre-operative CA was 1.13±0.20 D.There was a reduction of astigmatism at all post-operative visits(residual CA 1mo:0.85±0.42 D,P=0.0001;6mo:0.86±0.35 D,P=0001;and 12mo:0.90±0.39,P=0.0001).Alpins indices remained stable over 12mo.Overall,the cohort was under-corrected at all time points.At 12mo,61%of eyes were within±15 degrees of pre-operative astigmatic meridian.CONCLUSION:Unpaired unopened penetrating FAKs combined with on-axis phacoemulsification are safe but minimally effective.CA is largely under-corrected in this cohort using an existing unmodified nomogram.The effect of arcuate keratotomies on CA remained stable over 12mo.展开更多
Purpose: To investigate the efficacy of non-penetrating femtosecond laser intrastromal astigmatic keratotomy (ISAK) in terms of topographic and refractive changes. Methods: Retrospective study including 42 eyes (35 pa...Purpose: To investigate the efficacy of non-penetrating femtosecond laser intrastromal astigmatic keratotomy (ISAK) in terms of topographic and refractive changes. Methods: Retrospective study including 42 eyes (35 patients) with a corneal astigmatism between 0.5 and 1.5 D. All eyes underwent femtosecond laser-assisted cataract surgery with ISAK for astigmatism management using the Catalys laser system (Johnson & Johnson Vision). Visual acuity, refraction, as well as corneal topographic and corneal endothelial cell density (ECD) changes were evaluated during a 12-month follow-up. Astigmatic changes were analyzed using the Alpins vector method. Results: A significant reduction in manifest cylinder was observed at 1 month postoperatively (p = 0.03), with no significant changes afterwards (p = 0.90). A total of 38.1%, 52.4% and 59.2% of eyes had a manifest cylinder of 0.50 D or lower preoperatively and at 1 and 12 months after surgery, respectively. A significant reduction was found in topographic astigmatism at 1 month postoperatively (p < 0.01), with an additionally small but statistically significant reduction afterwards (p < 0.01). No significant changes in postoperative uncorrected (p = 0.97) and corrected visual acuities (p = 0.40) were observed during the follow-up. There was a trend to undercorrection of corneal astigmatism that decreased significantly over time. This led to some variability in changes of refractive astigmatism. A small but significant reduction in ECD was observed at 1 month postoperatively (p Conclusions: Femtosecond laser assisted ISAK is an effective and safe option to reduce corneal astigmatism during cataract surgery and consequently refractive astigmatism.展开更多
The high frequency gravitational waves （around lOS-lO12 Hz） could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux （PPF） of a...The high frequency gravitational waves （around lOS-lO12 Hz） could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux （PPF） of an electromagnetic resonance system can be improved significantly by virtue of an astigmatic Caussian beam. Cor- respondingly the signal-to-noise ratio （SNR） would also be improved. When the eccentric ratio of waist satisfying w0x ： w0y 〉 1, the peak value of signal photon flux could be raised by 2-4 times with typical systematic parameters, while the background photon flux would be depressed. Therefore, the ratio of transverse PPF to background photon flux （i.e., SNR） can be further improved 3-8 times with dimensionless amplitude of relic gravitational wave ht = 10-36.展开更多
Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically...Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically induced high corneal astigmatism by laser thermal keratoplasty(LTK)in a patient with cataract who was successfully treated with simultaneous combination of FSAK and toric IOL implantation with femtosecond laser-assisted cataract surgery(FLACS).This is the first report of both procedures combined simultaneously,with or without history of LTK.Case Description:A 68-year-old male presented with a history of LTK with two enhancements each eye in 2004,with subsequent surgically induced high corneal astigmatism,and with age-related nuclear cataract of both eyes.IOL master demonstrated+7.71 diopters of astigmatism at 163 degree right eye and+3.29 diopters of astigmatism at 4 degree left eye.After extensive discussion of the risks and benefits,the patient agreed to undergo FLACS with FSAK with two 61 degrees of relaxation incisions(RIs)and toric IOL(Alcon SN6AT9)right eye;FLACS with toric IOL(Alcon SN6AT7)alone left eye.At 2-year follow-up,uncorrected visual acuity was 20/30 right eye,20/25 left eye.His best corrected visual acuity was 20/25(+0.25+1.00 axis 21)right eye and 20/20(plano+0.25 axis 90)left eye;his best corrected near visual acuity was J1+with add+2.50 diopters right eye and left eye.Conclusions:Patients with age-related cataract and LTK induced high corneal astigmatism can hardly be sufficiently treated with FSAK or toric IOL alone at the time of cataract surgery.An effective way is to combine large FSAK and toric IOL of the highest cylindrical power of T9,in our case,simultaneously,which can achieve an excellent long term visual outcome.展开更多
AIM:To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis(LASIK)in eyes with myopic astigmatism using wavefront-guided(WFG)and wavefront-optimized(WFO)ablation pr...AIM:To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis(LASIK)in eyes with myopic astigmatism using wavefront-guided(WFG)and wavefront-optimized(WFO)ablation profiles.METHODS:Prospective study included 221 eyes undergoing LASIK:99 and 122 eyes with low and moderate myopic astigmatism(low and moderate myopia groups).Two subgroups were differentiated in each group according to the ablation profile:WFG subgroup,109 eyes(45/64,low/moderate myopia groups)treated using the Advanced Custom Vue platform(Abbott Medical Optics Inc.),and WFO subgroup,112 eyes(54/58,low/moderate myopia groups)treated using the EX-500 platform(Alcon).Clinical outcomes were evaluated during a 6-month follow-up,including a vector analysis of astigmatic changes.RESULTS:Significantly better postoperative uncorrected visual acuity and efficacy index was found in the WFG subgroups of each group(P≤0.041).Postoperative spherical equivalent and cylinder were significantly higher in WFO subgroups(P≤0.003).In moderate myopia group,a higher percentage of eyes with a postoperative cylinder≤0.25 D was found in the WFG subgroup(90.6%vs 65.5%,P=0.002).In low and moderate myopia groups,the difference vector was significantly higher in the WFO subgroup compared to WFG(P〈0.001).In moderate myopia group,the magnitude(P=0.008)and angle of error(P〈0.001)were also significantly higher in the WFO subgroup.Significantlyless induction of high order aberrations were found with WFG treatments in both low and moderate myopia groups(P≤0.006).CONCLUSION:A more efficacious correction of myopic astigmatism providing a better visual outcome is achieved with WFG LASIK compared to WFO LASIK.展开更多
AIM:To evaluate the light adjustable lens(LAL)vs a standard monofocal lens in achieving target astigmatic refraction and improving postoperative uncorrected distance visual acuity(UDVA).METHODS:This randomized control...AIM:To evaluate the light adjustable lens(LAL)vs a standard monofocal lens in achieving target astigmatic refraction and improving postoperative uncorrected distance visual acuity(UDVA).METHODS:This randomized controlled clinical trial included 40 patients with pre-existing astigmatism and visually significant cataract.Twenty-eight patients received the LAL and 12 control patients received a monofocal intraocular lens(IOL)after cataract extraction at a single institution.The patients with the LAL underwent adjustment by ultraviolet(UV)light postoperatively plus subsequent lock-in procedures and all patients returned to clinic for follow up of study parameters at 6,9,and 12 mo.Manifest refraction,distance visual acuity,and adverse events were recorded at each visit.RESULTS:The mean cylinder before adjustment in eyes with the LAL was-0.89±0.58 D(-2.00 to 0.00 D)and-0.34±0.34 D(-1.25 to 0.00 D)after lock-in(P=1.68 x10-8).The mean cylinder in patients with the monofocal lens was-1.00±0.32 D(-1.50 to-0.50 D)at 17-21 d postoperatively,which was statistically different from the LAL cylinder postlock-in(P=1.43 x10-6).UDVA in the LAL group was 20/20 or better in 79%of patients post lock-in with good stability over 12 mo compared with 33%of the control patients with UDVA of 20/20 or better.CONCLUSION:These results demonstrate that the LAL is more effective in achieving target refractions and improving postoperative UDVA in patients with pre-existing corneal astigmatism than a standard monofocal lens.展开更多
Myopia and astigmatism, two common refractive errors frequently co-exist, are degrading vision at all working distances in populations worldwide. Eyeballs having high degrees of myopia and astigmatism are known to exh...Myopia and astigmatism, two common refractive errors frequently co-exist, are degrading vision at all working distances in populations worldwide. Eyeballs having high degrees of myopia and astigmatism are known to exhibit abnormal eye shape at the anterior and posterior eye segments, but whether the outer coats of these abnormal eyeballs, cornea anteriorly and sclera posteriorly, are regulated by region-specific molecular mechanism remains unclear. Here we presented the changes in eye shape and mRNA expression levels of three genes (MMP2, TIMP2, and TGFB2), all known to participate in extracellular matrix organization, at five regions of the cornea and sclera in chickens developing high myopia and astigmatism induced by form deprivation. Our results showed that, compared to normal chicks, the highly myopic-astigmatic chicks had significantly astigmatic cornea, deeper anterior chamber, longer axial length, and higher expressions of all three genes in the superior sclera. These results imply that local molecular mechanism may manipulate the eye’s structural remodeling across the globe during refractive eye growth.展开更多
This paper studies the focusing properties of Gaussian Schell-model （GSM） beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of fo...This paper studies the focusing properties of Gaussian Schell-model （GSM） beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of focused GSM beams by an astigmatic aperture lens depend upon the astigmatism of the lens, the coherence of partially coherent light, the truncation parameter of the aperture and Fresnel number. The numerical calculation results are given to illustrate how these parameters affect the focusing property.展开更多
Background:Astigmatic keratotomy(AK)remains an accessible means to correct surgically induced or naturally occurring astigmatism.The advantages of femtosecond laser-assisted astigmatic keratotomy(FSAK)over conventiona...Background:Astigmatic keratotomy(AK)remains an accessible means to correct surgically induced or naturally occurring astigmatism.The advantages of femtosecond laser-assisted astigmatic keratotomy(FSAK)over conventional methods have been recognized recently.Main text:This review evaluates the efficacy,complications,and different methods of FSAK for correction of astigmatism in native eyes and those that underwent previous penetrating keratoplasty(PKP).The penetrating and intrastromal FSAK(IFSAK)techniques can reduce post-keratoplasty astigmatism by 35.4%to 84.77%and 23.53%to 89.42%,respectively.In native eyes,the penetrating and IFSAK techniques reduce astigmatism by 26.8%to 58.62%and 36.3%to 58%respectively,implying that the magnitude of the astigmatic reduction is comparable between the two FSAK procedures.Nonetheless,IFSAK offers the additional advantages of almost no risk of infection,wound gape,and epithelial ingrowth.The use of nomograms,anterior-segment optical coherence tomography,and consideration of posterior cornea and corneal biomechanics are helpful to enhance the efficacy and safety of FSAK.The complications of FSAK in eyes that underwent PKP include overcorrection,visual loss,microperforations,infectious keratitis,allograft rejection,and endophthalmitis.The reported difficulties in native eyes include overcorrection,anterior gas breakthrough,and suction loss.Conclusions:In eyes that underwent PKP,FSAK effectively reduces high regular or irregular astigmatism,with rare and manageable complications.Nevertheless,the drawbacks of the procedure include the potential loss of visual acuity and low predictability.For native eyes undergoing femtosecond laser-assisted cataract surgery,IFSAK is a good choice to correct low astigmatism(<1.5 diopters).The refractive effect of astigmatism from the posterior cornea needs to be considered in the nomograms for native eyes undergoing refractive cataract surgery.To further improve the efficacy of FSAK,more large-scale randomized studies with longer follow-up are needed.展开更多
Background:To compare the outcomes of a toric phakic intraocular lens(PIOL)and a spherical PIOL combined with astigmatic keratotomy(AK)for the correction of high myopic astigmatism.Methods:This study enrolled patients...Background:To compare the outcomes of a toric phakic intraocular lens(PIOL)and a spherical PIOL combined with astigmatic keratotomy(AK)for the correction of high myopic astigmatism.Methods:This study enrolled patients with high myopic astigmatism,including 30 eyes(22 patients)that received a toric PIOL implantation(TICL group),and 32 eyes(24 patients)that received combined AK and a spherical PIOL implantation(AK+ICL group).The outcomes were compared between the two groups before surgery,and at the following time points after surgery:1 week,1,3,6 months,and 1,2 years.Results:Preoperatively,the mean manifest spherical equivalent(SE)was−14.14±2.12 D in the TICL group and−14.83±2.79 D in the AK+ICL group(P=0.28),and the mean manifest refractive cylinder,−2.87±1.09 D and−2.58±0.85 D,respectively(P=0.28).Two years postoperatively,the mean safety index was 1.53±0.55 in the TICL group and 1.60±0.70 in the AK+ICL group(P=1.00),and the mean efficacy index,1.18±0.45 and 1.38±0.52,respectively(P=0.86).The mean manifest refractive cylinder correction was 1.94±1.07 D in the TICL group and 1.39±0.71 D in the AK+ICL group(P=0.02).The mean changes in SE and refractive cylinder from 1 week to 2 years were less than 0.50 D in both groups.Conclusions:Both TICL implantation and AK+ICL implantation are a good alternative for correction of astigmatism in addition to high myopia.TICL implantation has better predictability in correction of high myopic astigmatism.展开更多
Objective To compare the efficacy of toric implantable collamer lens(Toric-ICL)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)for myopia correction in patients with moderate to high myopia complicated ...Objective To compare the efficacy of toric implantable collamer lens(Toric-ICL)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)for myopia correction in patients with moderate to high myopia complicated with astigmatism.Methods We retrospectively collected data from 64 patients(aged 18-42 years)with moderate to high myopia complicated with astigmatism(128 eyes)undergoing either Toric-ICL(28 patients/56 eyes)or FS-LASIK(36 patients/72 eyes)at our department between January,2019 and December,2020.The changes of uncorrected distance visual acuity(UCVA),spherical equivalent(SE),mean astigmatism correction index(CI),corneal endothelial cell density(ECD)and intraocular pressure(IOP)following the procedures were compared between the two groups.Results In FS-LASIK group,all the eyes(72/72)achieved an UCVA≥1.0,similar to the rate in Toric-ICL group(55/56 eyes;P=0.2374).The postoperative SE was also comparable between FS-LASIK and Toric-ICL groups[0.43±0.06 D(range:-1.0 to 1.50 D)vs 0.38±0.05 D(range:-0.75 to 1.00 D);P=0.56].The mean astigmatism CI was significantly higher in FS-LASIK group than in Toric-ICL group(0.8561 vs 0.7176;P<0.0001),and 88.89%of the eyes in FS-LASIK group and 69.64%in Toric-ICL group had postoperative astigmatism≤0.50 D.No significant changes were observed in postoperative corneal ECD in FS-LASIK group,whereas ECD decreased significantly after the procedure in Toric-ICL group(P=0.0057).The patients undergoing Toric-ICL exhibited no significant changes of postoperative IOP,but the patients receiving FS-LASIK had significantly reduced IOP after the procedure(P<0.001).Conclusion Although the patients included in Toric-ICL group had higher myopia and astigmatism,Toric-ICL still showed better predictability and efficacy for astigmatic correction in Toric-ICL group.Toric-ICL is an effective and safe equivalent of FS-LASIK for correcting moderate myopia but can be more advantageous for correcting high myopia with astigmatism.展开更多
Cataract surgery is still the most common surgery performed worldwide.It has evolved tremendously in terms of incision,from 12 mm to 1.8 mm,in terms of capsulotomy from envelope type to automated capsulorhexis,and fro...Cataract surgery is still the most common surgery performed worldwide.It has evolved tremendously in terms of incision,from 12 mm to 1.8 mm,in terms of capsulotomy from envelope type to automated capsulorhexis,and from rigid intraocular lens to foldable intraocular lenses.Manual small incision cataract surgery(MSICS)remains a valuable technique,particularly in rural and underserved areas,due to its cost-effectiveness and simplicity.Its low logistics and favorable outcomes are particularly useful for managing the cataract backlog in developing countries.This review highlights the history and evolution of MSICS,and the reasons for the advent and popularity of this technique,especially in developing countries.It reviews the various recent modifications of the technique,for example,from a superior incision approach to temporal incision to customized MSICS,2 mm MSICS,and astigmatism-correcting MSICS.It provides an overview of its applicability in complicated scenarios(viz.,small pupil,compromised cornea,pseudoexfoliation,subluxated cataract,etc.).It briefly reviews the clinical trials on MSICS and its comparison with phacoemulsification.Finally,the review emphasizes why every ophthalmic surgeon must know MSICS,its relevance in postgraduate teaching,and the role of MSICS simulators for the same.Overall,the review presents a comprehensive picture of the present status of this technique in the surgical armamentarium of ophthalmology.展开更多
AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 childr...AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 children(252 eyes)with myopia and HAL treatment who were aged 7-13 and had rapid AL changes.The participants were divided into groups with AL reduction and elongation according to the changes in AL within 6mo.Paired t-tests were used to compare the ocular biological parameters at baseline and after rapid changes post-HAL treatment.Pearson’s correlation analysis was used to determine the association between the ocular parameters and AL changes.RESULTS:The ocular biological parameters significantly changed in the children with myopia and rapid AL changes after HAL treatment.In the group with AL reduction,the anterior chamber depth(ACD)and vitreous chamber depth(VCD)decreased.The crystalline lens thickness(CLT)increased,corneal flat keratometry(FK)decreased,and steep keratometry(SK)increased(all P<0.001).The eyes in the group with AL elongation had increased ACD and VCD and steepened SK,but the CLT or FK findings were not different.AL change was negatively associated with baseline astigmatism(r=-0.171;P=0.007).CONCLUSION:In the eyes with HAL treatment,decreased ACD and VCD,thickened CLT,flattened FK,and steepened SK are observed during AL reduction.Lower baseline astigmatism is associated with AL reduction.The AL reduction may suggest the potential efficacy of HAL intervention in myopia control,while providing evidence for optimizing personalized myopia management strategies.Further longitudinal studies are warranted to validate whether rapid AL changes predict sustained treatment efficacy.展开更多
AIM:To compare the accuracy of manual marking versus an image-guided system for toric implantable collamer lens(TICL)implantation and evaluate the short-term postoperative rotational stability of TICL and corneal surg...AIM:To compare the accuracy of manual marking versus an image-guided system for toric implantable collamer lens(TICL)implantation and evaluate the short-term postoperative rotational stability of TICL and corneal surgically induced astigmatism vector(SIA).METHODS:Retrospective analysis was conducted on eyes with TICL alignment achieved through manual marking(n=75)or VERION image-guided system-assisted marking(n=83).Each group was further classified into horizontal and vertical subgroups based on implant orientation.Additionally,patients were categorized into superior and temporal incision subgroups according to the position of main corneal incision.The misalignment and rotational stability of TICL were analyzed using slit-lamp anterior segment photography.Surgical predictability,efficacy,safety,and corneal SIA were also evaluated.RESULTS:In general,the TICL implantation with manual and digital image-guided systems all achieved robust predictability,efficacy,and safety.The misalignment of TICL was comparable between the manual and VERION groups(0.16°±3.97°vs 0.52°±5.59°,P=0.633),while a significant difference was observed in the absolute misalignment of TICL between the two groups(3.02°±2.55°vs 4.28°±3.61°,P=0.043).There were no significant differences in the distribution of TICL misalignment between the manual and VERION groups or between horizontal and vertical implant orientation groups(P>0.05).Furthermore,different orientations of TICL placement did not show statistically significant differences in rotational stability(P=0.46).Statistically significant differences were found in anterior corneal SIA between the manual and VERION groups(0.46±0.27 vs 0.33±0.21 D,P=0.001),especially for superior incision position(0.60±0.27 vs 0.35±0.23 D,P<0.0001).The anterior SIA exhibited a significant difference between superior and temporal incisions in the manual group(0.60±0.27 vs 0.35±0.20 D,P<0.0001).CONCLUSION:Compared with the conventional manual marking method,this study indicates that the digital image-guided system with VERION is safe and effective in TICL implantation.The digital system offers the advantage of minimizing corneal SIA compared to the manual method.展开更多
AIM:To compare the visual outcomes and corneal higherorder aberrations(HOAs)of patients with high or low myopic astigmatism after small incision lenticule extraction(SMILE).METHODS:A total of 157 eyes of 157 patients ...AIM:To compare the visual outcomes and corneal higherorder aberrations(HOAs)of patients with high or low myopic astigmatism after small incision lenticule extraction(SMILE).METHODS:A total of 157 eyes of 157 patients who underwent SMILE were included in this retrospective,nonrandomized,comparative study.All the eyes which were with the rule astigmatism were divided into high astigmatism group(HAG;astigmatism≤-2.00 D,73 eyes)and low astigmatism group(LAG;astigmatism≥-1.00 D,84 eyes).Visual and refractive examinations were performed,HOAs of the anterior surface,posterior surface,and total cornea of the eyes were evaluated preoperatively and 6mo postoperatively.RESULTS:At the postoperative 6-month follow-up,uncorrected distance visual acuity of 20/20 or better was achieved in 97%and 100%eyes in HAG and LAG respectively and 74%and 100%eyes were within-0.50 D.Vector analysis revealed no significant differences in the correction index(P=0.066),angle of error(P=0.091)or flattening index(P=0.987)between two groups.The magnitude of error was-0.37±0.31 D in HAG and-0.04±0.19 D in LAG(P<0.001).Index of success(IOS)was 0.22±0.09 in the HAG and 0.50±0.46 in the LAG(P<0.001).HOAs of most anterior,posterior and total cornea significantly increased after SMILE,especially the spherical aberration and coma.For HAG,the SMILE procedure induced significantly higher anterior,posterior and total cornea horizontal coma and total corneal total HOAs compared with LAG(P<0.001)and these surgically induced HOAs predominantly originated from the anterior surface of the cornea.CONCLUSION:SMILE surgery induces more HOAs and a mild under-correction of astigmatism in eyes with high astigmatism.The increment in HOAs after SMILE is related to preoperative astigmatism.展开更多
AIM:To compare the subjective refraction data with autorefraction findings in high astigmatisms.METHODS:In a cross-sectional study,sampling was done from in different geographic regions in Iran using a multistage rand...AIM:To compare the subjective refraction data with autorefraction findings in high astigmatisms.METHODS:In a cross-sectional study,sampling was done from in different geographic regions in Iran using a multistage random cluster sampling method.All study participants underwent cycloplegic auto-refraction and subjective refraction using the red-green test.RESULTS:In this study,277 eyes of 158 students aged 8 to 15y were analyzed.According to the results,the mean difference between subjective refraction and autorefraction in measuring sphere,cylinder,spherical equivalent,J0,and J45 was-0.18±0.76,-0.36±0.40,-0.36±0.79,0.15±0.20,and 0.05±0.21 respectively.The correlation of these two refraction methods in measuring the aforementioned indices was 0.963,0.898,0.960,0.931,and 0.948 respectively.The 95%limits of agreement of the two methods in measuring the above indices were-1.66 to 1.31,-1.14 to 0.42,-1.91 to 1.19,-0.24 to 0.54,and-0.36 to 0.47 respectively.The agreement between the two methods decreased with increasing cylinder power,and the best agreement was found in myopic individuals.CONCLUSION:The measurements obtained by autorefractometer have a significantly higher cylinder average compared to subjective refraction.However,in the cylinder range of 4–5 diopters,the values of J0 and J45 do not have a high correlation.展开更多
Background:To construct a real-time computerized location system(RCLS)to analyze and display the axis of corneal astigmatism and to compare its accuracy with the Scheimpflug method.Methods:Fifty-seven eyes of 39 volun...Background:To construct a real-time computerized location system(RCLS)to analyze and display the axis of corneal astigmatism and to compare its accuracy with the Scheimpflug method.Methods:Fifty-seven eyes of 39 volunteers with corneal astigmatism more than 1.00 diopter(D)were recruited.The RCLS was composed of a circular light-emitting diode(LED)light source,surgical microscope,surgical video system,computer and self-programming image analysis software.Scheimpflug imaging measurements(Pentacam HR,Oculus,Wetzlar,Germany)were performed on all subjects to determine the axis and power of corneal astigmatism.Thereafter,the axis of corneal astigmatism was analyzed in real-time and displayed by the RCLS on supine position,and videos were recorded.The MB-Ruler 4.0 software was used to measure the astigmatic axis.The accuracy of the RCLS was compared with the Scheimpflug method.Results:The RCLS was able to display the axis of corneal astigmatism in real-time.The axial deviation of corneal astigmatism between the two methods was 0.63±3.78°when astigmatism was 1.00 to 2.00 D and decreased to 0.06±1.38°when astigmatism was greater than 2.00 D.A linear correlation of astigmatic axis was noted between the two methods:Axis_(RCLS)=1.01×Axis_(Scheimpflug)−1.02(R^(2)=0.998,P<0.001).The Bland-Altman analysis revealed that the RCLS agreed sufficiently well with the Scheimpflug method.Conclusions:The RCLS can accurately analyze and display the axis for corneal astigmatism greater than 1.00 D in real-time.The RCLS simplifies marking procedures and may have potential clinical application to improve the postoperative visual outcomes in surgical correction of corneal astigmatism.展开更多
AIM:To investigate the effect of astigmatism and spherical equivalent(SE)correction on contrast sensitivity(CS).METHODS:In this cross-sectional study,103 visually normal subjects aged 18 to 36y with bilateral regular ...AIM:To investigate the effect of astigmatism and spherical equivalent(SE)correction on contrast sensitivity(CS).METHODS:In this cross-sectional study,103 visually normal subjects aged 18 to 36y with bilateral regular astigmatism in range of 1.00 diopter cylinder(DC)to 4.00 DC and normal best-corrected visual acuity(20/20)were recruited.Binocular CS was assessed by linear sine-wave gratings at 1.5,3,6,12,and 18 cycles per degree(cpd),before correction of astigmatism,after full correction of astigmatism by cylindrical spectacle lenses,and after SE of refractive error.The repeated measures ANOVA and Bonferroni test were used to compare the effects of astigmatism correction on logCS.RESULTS:Totally 39 patients were male and 64 patients were female with the mean age of 28.25±5.38y.The average degree of astigmatism in right and left eye was 2.03±0.83 and 2.10±0.78,respectively.Increases in uncorrected astigmatic power correlated with decreases in the logCS,especially at high spatial frequencies.A statistically significant difference in logCS was found between these three cases:before correction of astigmatism,after SE of refractive error,and after full correction of astigmatism by cylindrical spectacle lenses at all frequencies(P<0.001),except at 18 cpd.At 18 cpd,there was no statistically significant difference between logCS before and after SE of refractive error(P=1.0).Also,there was no statistically significant difference in mean CS between with-the-rule(WTR)and against-the-rule(ATR)astigmatism,before correction of astigmatism,after correction of astigmatism with cylindrical lenses,and after SE of refractive error.CONCLUSION:Binocular astigmatism defocus decreases CS depending on the degree of astigmatism power;correction of this will improve patent’s quality of vision.Although high astigmatism refractive error(more than 2.00 DC)that is fully corrected by cylindrical spectacle lenses doesn’t increase the CS to the maximum value,especially at higher spatial frequencies(12 and 18).Also SE refractive error effects on improving CS in low astigmatism power(less than 2.00 DC),especially at lower spatial frequencies.展开更多
Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the eye.It causes blurred vision at any distance and includes corneal,lenticular,and retinal...Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the eye.It causes blurred vision at any distance and includes corneal,lenticular,and retinal astigmatism.Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism,for example,a large size surgery incision.The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery.Nowadays,three surgical approaches can be used.By placing a sutureless clear corneal incision on the steep meridian of the cornea,a preoperative corneal astigmatism less than 1.0 D can be corrected.Single or paired peripheral corneal relaxing incisions(PCRIs)provide 1.0-3.0 D corneal astigmatism correction.PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism,if more than 2.0 D,the risk of overcorrection and irregular astigmatism is increased.When toric intraocular lenses(IOLs)are unavailable in markets,PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism.Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism.Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D.These approaches can be used alone or in combination.展开更多
AIM:To describe the distribution of refractive errors by age and sex among schoolchildren in Soacha,Colombia.METHODS:This was an observational cross-sectional study conducted in five urban public schools in the munici...AIM:To describe the distribution of refractive errors by age and sex among schoolchildren in Soacha,Colombia.METHODS:This was an observational cross-sectional study conducted in five urban public schools in the municipality of Soacha.A total of 1161 school-aged and pre-adolescent children,aged 5-12y were examined during the school year 2021-2022.Examinations included visual acuity and static refraction.Spherical equivalent(SE)was analysed as follows:myopia SE≤-0.50 D and uncorrected visual acuity of 20/25 or worse;high myopia SE≤-6.00 D;hyperopia SE≥+1.00 D(≥7y)or SE≥+2.00 D(5-6y);significant hyperopia SE≥+3.00 D.Astigmatism was defined as a cylinder in at least one eye≥1.00 D(≥7y)or≥1.75 D(5-6y).If at least one eye was ametropic,children were classified according to the refractive error found.RESULTS:Of the 1139 schoolchildren included,50.6%were male,58.8%were aged between 5 and 9y,and 12.1%were already using optical correction.The most common refractive error was astigmatism(31.1%),followed by myopia(20.8%)and hyperopia(13.1%).There was no significant relationship between refractive error and sex.There was a significant increase in astigmatism(P<0.001)and myopia(P<0.0001)with age.CONCLUSION:Astigmatism is the most common refractive error in children in an urban area of Colombia.Emmetropia decreased and myopia increased with age.展开更多
基金Supported by independent research grant from Alcon(IIT#34114517)。
文摘AIM:To evaluate corneal astigmatic outcomes of femtosecond laser-assisted arcuate keratotomies(FAKs)combined with femtosecond-laser assisted cataract surgery(FLACS)over 12mo follow-up.METHODS:Totally 145 patients with bilateral cataracts and no ocular co-morbidities were recruited to a singlecentre,single-masked,prospective randomized controlled trial(RCT)comparing two monofocal hydrophobic acrylic intraocular lenses.Eyes with corneal astigmatism(CA)of>0.8 dioptres(D)received unpaired,unopened,surface penetrating FAKs at the time of FLACS.Visual acuity,subjective refraction and Scheimpflug tomography were recorded at 1,6,and 12mo.Alpins vectoral analyses were performed.RESULTS:Fifty-one patients(61 eyes),mean age 68.2±9.6y[standard deviation(SD)],received FAKs.Sixty eyes were available for analysis,except at 12mo when 59 attended.There were no complications due to FAKs.Mean pre-operative CA was 1.13±0.20 D.There was a reduction of astigmatism at all post-operative visits(residual CA 1mo:0.85±0.42 D,P=0.0001;6mo:0.86±0.35 D,P=0001;and 12mo:0.90±0.39,P=0.0001).Alpins indices remained stable over 12mo.Overall,the cohort was under-corrected at all time points.At 12mo,61%of eyes were within±15 degrees of pre-operative astigmatic meridian.CONCLUSION:Unpaired unopened penetrating FAKs combined with on-axis phacoemulsification are safe but minimally effective.CA is largely under-corrected in this cohort using an existing unmodified nomogram.The effect of arcuate keratotomies on CA remained stable over 12mo.
文摘Purpose: To investigate the efficacy of non-penetrating femtosecond laser intrastromal astigmatic keratotomy (ISAK) in terms of topographic and refractive changes. Methods: Retrospective study including 42 eyes (35 patients) with a corneal astigmatism between 0.5 and 1.5 D. All eyes underwent femtosecond laser-assisted cataract surgery with ISAK for astigmatism management using the Catalys laser system (Johnson & Johnson Vision). Visual acuity, refraction, as well as corneal topographic and corneal endothelial cell density (ECD) changes were evaluated during a 12-month follow-up. Astigmatic changes were analyzed using the Alpins vector method. Results: A significant reduction in manifest cylinder was observed at 1 month postoperatively (p = 0.03), with no significant changes afterwards (p = 0.90). A total of 38.1%, 52.4% and 59.2% of eyes had a manifest cylinder of 0.50 D or lower preoperatively and at 1 and 12 months after surgery, respectively. A significant reduction was found in topographic astigmatism at 1 month postoperatively (p < 0.01), with an additionally small but statistically significant reduction afterwards (p < 0.01). No significant changes in postoperative uncorrected (p = 0.97) and corrected visual acuities (p = 0.40) were observed during the follow-up. There was a trend to undercorrection of corneal astigmatism that decreased significantly over time. This led to some variability in changes of refractive astigmatism. A small but significant reduction in ECD was observed at 1 month postoperatively (p Conclusions: Femtosecond laser assisted ISAK is an effective and safe option to reduce corneal astigmatism during cataract surgery and consequently refractive astigmatism.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11205254 and 61501069the Fundamental Research Funds for the Central Universities under Grant No 106112016CDJXY300002
文摘The high frequency gravitational waves （around lOS-lO12 Hz） could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux （PPF） of an electromagnetic resonance system can be improved significantly by virtue of an astigmatic Caussian beam. Cor- respondingly the signal-to-noise ratio （SNR） would also be improved. When the eccentric ratio of waist satisfying w0x ： w0y 〉 1, the peak value of signal photon flux could be raised by 2-4 times with typical systematic parameters, while the background photon flux would be depressed. Therefore, the ratio of transverse PPF to background photon flux （i.e., SNR） can be further improved 3-8 times with dimensionless amplitude of relic gravitational wave ht = 10-36.
文摘Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically induced high corneal astigmatism by laser thermal keratoplasty(LTK)in a patient with cataract who was successfully treated with simultaneous combination of FSAK and toric IOL implantation with femtosecond laser-assisted cataract surgery(FLACS).This is the first report of both procedures combined simultaneously,with or without history of LTK.Case Description:A 68-year-old male presented with a history of LTK with two enhancements each eye in 2004,with subsequent surgically induced high corneal astigmatism,and with age-related nuclear cataract of both eyes.IOL master demonstrated+7.71 diopters of astigmatism at 163 degree right eye and+3.29 diopters of astigmatism at 4 degree left eye.After extensive discussion of the risks and benefits,the patient agreed to undergo FLACS with FSAK with two 61 degrees of relaxation incisions(RIs)and toric IOL(Alcon SN6AT9)right eye;FLACS with toric IOL(Alcon SN6AT7)alone left eye.At 2-year follow-up,uncorrected visual acuity was 20/30 right eye,20/25 left eye.His best corrected visual acuity was 20/25(+0.25+1.00 axis 21)right eye and 20/20(plano+0.25 axis 90)left eye;his best corrected near visual acuity was J1+with add+2.50 diopters right eye and left eye.Conclusions:Patients with age-related cataract and LTK induced high corneal astigmatism can hardly be sufficiently treated with FSAK or toric IOL alone at the time of cataract surgery.An effective way is to combine large FSAK and toric IOL of the highest cylindrical power of T9,in our case,simultaneously,which can achieve an excellent long term visual outcome.
基金Partially supported by a grant from Abbott Medical Optics
文摘AIM:To evaluate and compare the efficacy of the astigmatic correction achieved with laser in situ keratomileusis(LASIK)in eyes with myopic astigmatism using wavefront-guided(WFG)and wavefront-optimized(WFO)ablation profiles.METHODS:Prospective study included 221 eyes undergoing LASIK:99 and 122 eyes with low and moderate myopic astigmatism(low and moderate myopia groups).Two subgroups were differentiated in each group according to the ablation profile:WFG subgroup,109 eyes(45/64,low/moderate myopia groups)treated using the Advanced Custom Vue platform(Abbott Medical Optics Inc.),and WFO subgroup,112 eyes(54/58,low/moderate myopia groups)treated using the EX-500 platform(Alcon).Clinical outcomes were evaluated during a 6-month follow-up,including a vector analysis of astigmatic changes.RESULTS:Significantly better postoperative uncorrected visual acuity and efficacy index was found in the WFG subgroups of each group(P≤0.041).Postoperative spherical equivalent and cylinder were significantly higher in WFO subgroups(P≤0.003).In moderate myopia group,a higher percentage of eyes with a postoperative cylinder≤0.25 D was found in the WFG subgroup(90.6%vs 65.5%,P=0.002).In low and moderate myopia groups,the difference vector was significantly higher in the WFO subgroup compared to WFG(P〈0.001).In moderate myopia group,the magnitude(P=0.008)and angle of error(P〈0.001)were also significantly higher in the WFO subgroup.Significantlyless induction of high order aberrations were found with WFG treatments in both low and moderate myopia groups(P≤0.006).CONCLUSION:A more efficacious correction of myopic astigmatism providing a better visual outcome is achieved with WFG LASIK compared to WFO LASIK.
基金Supported by Research to Prevent Blindness(New York,New York)the clinical trial was sponsored by Rx Sight Inc.(formerly Calhoun Vision)
文摘AIM:To evaluate the light adjustable lens(LAL)vs a standard monofocal lens in achieving target astigmatic refraction and improving postoperative uncorrected distance visual acuity(UDVA).METHODS:This randomized controlled clinical trial included 40 patients with pre-existing astigmatism and visually significant cataract.Twenty-eight patients received the LAL and 12 control patients received a monofocal intraocular lens(IOL)after cataract extraction at a single institution.The patients with the LAL underwent adjustment by ultraviolet(UV)light postoperatively plus subsequent lock-in procedures and all patients returned to clinic for follow up of study parameters at 6,9,and 12 mo.Manifest refraction,distance visual acuity,and adverse events were recorded at each visit.RESULTS:The mean cylinder before adjustment in eyes with the LAL was-0.89±0.58 D(-2.00 to 0.00 D)and-0.34±0.34 D(-1.25 to 0.00 D)after lock-in(P=1.68 x10-8).The mean cylinder in patients with the monofocal lens was-1.00±0.32 D(-1.50 to-0.50 D)at 17-21 d postoperatively,which was statistically different from the LAL cylinder postlock-in(P=1.43 x10-6).UDVA in the LAL group was 20/20 or better in 79%of patients post lock-in with good stability over 12 mo compared with 33%of the control patients with UDVA of 20/20 or better.CONCLUSION:These results demonstrate that the LAL is more effective in achieving target refractions and improving postoperative UDVA in patients with pre-existing corneal astigmatism than a standard monofocal lens.
文摘Myopia and astigmatism, two common refractive errors frequently co-exist, are degrading vision at all working distances in populations worldwide. Eyeballs having high degrees of myopia and astigmatism are known to exhibit abnormal eye shape at the anterior and posterior eye segments, but whether the outer coats of these abnormal eyeballs, cornea anteriorly and sclera posteriorly, are regulated by region-specific molecular mechanism remains unclear. Here we presented the changes in eye shape and mRNA expression levels of three genes (MMP2, TIMP2, and TGFB2), all known to participate in extracellular matrix organization, at five regions of the cornea and sclera in chickens developing high myopia and astigmatism induced by form deprivation. Our results showed that, compared to normal chicks, the highly myopic-astigmatic chicks had significantly astigmatic cornea, deeper anterior chamber, longer axial length, and higher expressions of all three genes in the superior sclera. These results imply that local molecular mechanism may manipulate the eye’s structural remodeling across the globe during refractive eye growth.
基金Project supported by the Natural Science Foundation of Henan Province, China （Grant No 0611054000）.
文摘This paper studies the focusing properties of Gaussian Schell-model （GSM） beams by an astigmatic aperture lens. It is shown that the axial irradiance distribution, the maximum axial irradiance and its position of focused GSM beams by an astigmatic aperture lens depend upon the astigmatism of the lens, the coherence of partially coherent light, the truncation parameter of the aperture and Fresnel number. The numerical calculation results are given to illustrate how these parameters affect the focusing property.
文摘Background:Astigmatic keratotomy(AK)remains an accessible means to correct surgically induced or naturally occurring astigmatism.The advantages of femtosecond laser-assisted astigmatic keratotomy(FSAK)over conventional methods have been recognized recently.Main text:This review evaluates the efficacy,complications,and different methods of FSAK for correction of astigmatism in native eyes and those that underwent previous penetrating keratoplasty(PKP).The penetrating and intrastromal FSAK(IFSAK)techniques can reduce post-keratoplasty astigmatism by 35.4%to 84.77%and 23.53%to 89.42%,respectively.In native eyes,the penetrating and IFSAK techniques reduce astigmatism by 26.8%to 58.62%and 36.3%to 58%respectively,implying that the magnitude of the astigmatic reduction is comparable between the two FSAK procedures.Nonetheless,IFSAK offers the additional advantages of almost no risk of infection,wound gape,and epithelial ingrowth.The use of nomograms,anterior-segment optical coherence tomography,and consideration of posterior cornea and corneal biomechanics are helpful to enhance the efficacy and safety of FSAK.The complications of FSAK in eyes that underwent PKP include overcorrection,visual loss,microperforations,infectious keratitis,allograft rejection,and endophthalmitis.The reported difficulties in native eyes include overcorrection,anterior gas breakthrough,and suction loss.Conclusions:In eyes that underwent PKP,FSAK effectively reduces high regular or irregular astigmatism,with rare and manageable complications.Nevertheless,the drawbacks of the procedure include the potential loss of visual acuity and low predictability.For native eyes undergoing femtosecond laser-assisted cataract surgery,IFSAK is a good choice to correct low astigmatism(<1.5 diopters).The refractive effect of astigmatism from the posterior cornea needs to be considered in the nomograms for native eyes undergoing refractive cataract surgery.To further improve the efficacy of FSAK,more large-scale randomized studies with longer follow-up are needed.
基金funded by the Nature and Science Foundation of China(Grant No.81570869)Nature and Science Foundation of Zhejiang Province,China(Grant No.Y2110784)+2 种基金Zhejiang Provincial Foundation of China for Distinguished Young Talents in Medicine and Health(Grant No.2010QNA018)Foundation of Wenzhou City Science&Technology Bureau(Grant No.Y20140705)Engineering Development Project of Ophthalmology and Optometry(Grant No.GCKF201601).
文摘Background:To compare the outcomes of a toric phakic intraocular lens(PIOL)and a spherical PIOL combined with astigmatic keratotomy(AK)for the correction of high myopic astigmatism.Methods:This study enrolled patients with high myopic astigmatism,including 30 eyes(22 patients)that received a toric PIOL implantation(TICL group),and 32 eyes(24 patients)that received combined AK and a spherical PIOL implantation(AK+ICL group).The outcomes were compared between the two groups before surgery,and at the following time points after surgery:1 week,1,3,6 months,and 1,2 years.Results:Preoperatively,the mean manifest spherical equivalent(SE)was−14.14±2.12 D in the TICL group and−14.83±2.79 D in the AK+ICL group(P=0.28),and the mean manifest refractive cylinder,−2.87±1.09 D and−2.58±0.85 D,respectively(P=0.28).Two years postoperatively,the mean safety index was 1.53±0.55 in the TICL group and 1.60±0.70 in the AK+ICL group(P=1.00),and the mean efficacy index,1.18±0.45 and 1.38±0.52,respectively(P=0.86).The mean manifest refractive cylinder correction was 1.94±1.07 D in the TICL group and 1.39±0.71 D in the AK+ICL group(P=0.02).The mean changes in SE and refractive cylinder from 1 week to 2 years were less than 0.50 D in both groups.Conclusions:Both TICL implantation and AK+ICL implantation are a good alternative for correction of astigmatism in addition to high myopia.TICL implantation has better predictability in correction of high myopic astigmatism.
文摘Objective To compare the efficacy of toric implantable collamer lens(Toric-ICL)and femtosecond laser-assisted in situ keratomileusis(FS-LASIK)for myopia correction in patients with moderate to high myopia complicated with astigmatism.Methods We retrospectively collected data from 64 patients(aged 18-42 years)with moderate to high myopia complicated with astigmatism(128 eyes)undergoing either Toric-ICL(28 patients/56 eyes)or FS-LASIK(36 patients/72 eyes)at our department between January,2019 and December,2020.The changes of uncorrected distance visual acuity(UCVA),spherical equivalent(SE),mean astigmatism correction index(CI),corneal endothelial cell density(ECD)and intraocular pressure(IOP)following the procedures were compared between the two groups.Results In FS-LASIK group,all the eyes(72/72)achieved an UCVA≥1.0,similar to the rate in Toric-ICL group(55/56 eyes;P=0.2374).The postoperative SE was also comparable between FS-LASIK and Toric-ICL groups[0.43±0.06 D(range:-1.0 to 1.50 D)vs 0.38±0.05 D(range:-0.75 to 1.00 D);P=0.56].The mean astigmatism CI was significantly higher in FS-LASIK group than in Toric-ICL group(0.8561 vs 0.7176;P<0.0001),and 88.89%of the eyes in FS-LASIK group and 69.64%in Toric-ICL group had postoperative astigmatism≤0.50 D.No significant changes were observed in postoperative corneal ECD in FS-LASIK group,whereas ECD decreased significantly after the procedure in Toric-ICL group(P=0.0057).The patients undergoing Toric-ICL exhibited no significant changes of postoperative IOP,but the patients receiving FS-LASIK had significantly reduced IOP after the procedure(P<0.001).Conclusion Although the patients included in Toric-ICL group had higher myopia and astigmatism,Toric-ICL still showed better predictability and efficacy for astigmatic correction in Toric-ICL group.Toric-ICL is an effective and safe equivalent of FS-LASIK for correcting moderate myopia but can be more advantageous for correcting high myopia with astigmatism.
文摘Cataract surgery is still the most common surgery performed worldwide.It has evolved tremendously in terms of incision,from 12 mm to 1.8 mm,in terms of capsulotomy from envelope type to automated capsulorhexis,and from rigid intraocular lens to foldable intraocular lenses.Manual small incision cataract surgery(MSICS)remains a valuable technique,particularly in rural and underserved areas,due to its cost-effectiveness and simplicity.Its low logistics and favorable outcomes are particularly useful for managing the cataract backlog in developing countries.This review highlights the history and evolution of MSICS,and the reasons for the advent and popularity of this technique,especially in developing countries.It reviews the various recent modifications of the technique,for example,from a superior incision approach to temporal incision to customized MSICS,2 mm MSICS,and astigmatism-correcting MSICS.It provides an overview of its applicability in complicated scenarios(viz.,small pupil,compromised cornea,pseudoexfoliation,subluxated cataract,etc.).It briefly reviews the clinical trials on MSICS and its comparison with phacoemulsification.Finally,the review emphasizes why every ophthalmic surgeon must know MSICS,its relevance in postgraduate teaching,and the role of MSICS simulators for the same.Overall,the review presents a comprehensive picture of the present status of this technique in the surgical armamentarium of ophthalmology.
基金Supported by the Medical Science and Technology Project of Zhejiang Province of China(No.2020KY191).
文摘AIM:To investigate the ocular biological characteristics of children with myopia and rapid axial length(AL)changes prescribed spectacles with highly aspherical lenslets(HAL).METHODS:Data were collected from 156 children(252 eyes)with myopia and HAL treatment who were aged 7-13 and had rapid AL changes.The participants were divided into groups with AL reduction and elongation according to the changes in AL within 6mo.Paired t-tests were used to compare the ocular biological parameters at baseline and after rapid changes post-HAL treatment.Pearson’s correlation analysis was used to determine the association between the ocular parameters and AL changes.RESULTS:The ocular biological parameters significantly changed in the children with myopia and rapid AL changes after HAL treatment.In the group with AL reduction,the anterior chamber depth(ACD)and vitreous chamber depth(VCD)decreased.The crystalline lens thickness(CLT)increased,corneal flat keratometry(FK)decreased,and steep keratometry(SK)increased(all P<0.001).The eyes in the group with AL elongation had increased ACD and VCD and steepened SK,but the CLT or FK findings were not different.AL change was negatively associated with baseline astigmatism(r=-0.171;P=0.007).CONCLUSION:In the eyes with HAL treatment,decreased ACD and VCD,thickened CLT,flattened FK,and steepened SK are observed during AL reduction.Lower baseline astigmatism is associated with AL reduction.The AL reduction may suggest the potential efficacy of HAL intervention in myopia control,while providing evidence for optimizing personalized myopia management strategies.Further longitudinal studies are warranted to validate whether rapid AL changes predict sustained treatment efficacy.
文摘AIM:To compare the accuracy of manual marking versus an image-guided system for toric implantable collamer lens(TICL)implantation and evaluate the short-term postoperative rotational stability of TICL and corneal surgically induced astigmatism vector(SIA).METHODS:Retrospective analysis was conducted on eyes with TICL alignment achieved through manual marking(n=75)or VERION image-guided system-assisted marking(n=83).Each group was further classified into horizontal and vertical subgroups based on implant orientation.Additionally,patients were categorized into superior and temporal incision subgroups according to the position of main corneal incision.The misalignment and rotational stability of TICL were analyzed using slit-lamp anterior segment photography.Surgical predictability,efficacy,safety,and corneal SIA were also evaluated.RESULTS:In general,the TICL implantation with manual and digital image-guided systems all achieved robust predictability,efficacy,and safety.The misalignment of TICL was comparable between the manual and VERION groups(0.16°±3.97°vs 0.52°±5.59°,P=0.633),while a significant difference was observed in the absolute misalignment of TICL between the two groups(3.02°±2.55°vs 4.28°±3.61°,P=0.043).There were no significant differences in the distribution of TICL misalignment between the manual and VERION groups or between horizontal and vertical implant orientation groups(P>0.05).Furthermore,different orientations of TICL placement did not show statistically significant differences in rotational stability(P=0.46).Statistically significant differences were found in anterior corneal SIA between the manual and VERION groups(0.46±0.27 vs 0.33±0.21 D,P=0.001),especially for superior incision position(0.60±0.27 vs 0.35±0.23 D,P<0.0001).The anterior SIA exhibited a significant difference between superior and temporal incisions in the manual group(0.60±0.27 vs 0.35±0.20 D,P<0.0001).CONCLUSION:Compared with the conventional manual marking method,this study indicates that the digital image-guided system with VERION is safe and effective in TICL implantation.The digital system offers the advantage of minimizing corneal SIA compared to the manual method.
文摘AIM:To compare the visual outcomes and corneal higherorder aberrations(HOAs)of patients with high or low myopic astigmatism after small incision lenticule extraction(SMILE).METHODS:A total of 157 eyes of 157 patients who underwent SMILE were included in this retrospective,nonrandomized,comparative study.All the eyes which were with the rule astigmatism were divided into high astigmatism group(HAG;astigmatism≤-2.00 D,73 eyes)and low astigmatism group(LAG;astigmatism≥-1.00 D,84 eyes).Visual and refractive examinations were performed,HOAs of the anterior surface,posterior surface,and total cornea of the eyes were evaluated preoperatively and 6mo postoperatively.RESULTS:At the postoperative 6-month follow-up,uncorrected distance visual acuity of 20/20 or better was achieved in 97%and 100%eyes in HAG and LAG respectively and 74%and 100%eyes were within-0.50 D.Vector analysis revealed no significant differences in the correction index(P=0.066),angle of error(P=0.091)or flattening index(P=0.987)between two groups.The magnitude of error was-0.37±0.31 D in HAG and-0.04±0.19 D in LAG(P<0.001).Index of success(IOS)was 0.22±0.09 in the HAG and 0.50±0.46 in the LAG(P<0.001).HOAs of most anterior,posterior and total cornea significantly increased after SMILE,especially the spherical aberration and coma.For HAG,the SMILE procedure induced significantly higher anterior,posterior and total cornea horizontal coma and total corneal total HOAs compared with LAG(P<0.001)and these surgically induced HOAs predominantly originated from the anterior surface of the cornea.CONCLUSION:SMILE surgery induces more HOAs and a mild under-correction of astigmatism in eyes with high astigmatism.The increment in HOAs after SMILE is related to preoperative astigmatism.
基金Supported by Shahid Beheshti University of Medical Sciences.
文摘AIM:To compare the subjective refraction data with autorefraction findings in high astigmatisms.METHODS:In a cross-sectional study,sampling was done from in different geographic regions in Iran using a multistage random cluster sampling method.All study participants underwent cycloplegic auto-refraction and subjective refraction using the red-green test.RESULTS:In this study,277 eyes of 158 students aged 8 to 15y were analyzed.According to the results,the mean difference between subjective refraction and autorefraction in measuring sphere,cylinder,spherical equivalent,J0,and J45 was-0.18±0.76,-0.36±0.40,-0.36±0.79,0.15±0.20,and 0.05±0.21 respectively.The correlation of these two refraction methods in measuring the aforementioned indices was 0.963,0.898,0.960,0.931,and 0.948 respectively.The 95%limits of agreement of the two methods in measuring the above indices were-1.66 to 1.31,-1.14 to 0.42,-1.91 to 1.19,-0.24 to 0.54,and-0.36 to 0.47 respectively.The agreement between the two methods decreased with increasing cylinder power,and the best agreement was found in myopic individuals.CONCLUSION:The measurements obtained by autorefractometer have a significantly higher cylinder average compared to subjective refraction.However,in the cylinder range of 4–5 diopters,the values of J0 and J45 do not have a high correlation.
基金funded by the Nature and Science Foundation of China(Grant No.81570869)Nature and Science Foundation of Zhejiang Province,China(Grant No.Y2110784)+2 种基金Zhejiang Provincial Foundation of China for Distinguished Young Talents in Medicine and Health(Grant No.2010QNA018)Foundation of Wenzhou City Science&Technology Bureau(Grant No.Y20140705)Engineering Development Project of Ophthalmology and Optometry(Grant No.GCKF201601).
文摘Background:To construct a real-time computerized location system(RCLS)to analyze and display the axis of corneal astigmatism and to compare its accuracy with the Scheimpflug method.Methods:Fifty-seven eyes of 39 volunteers with corneal astigmatism more than 1.00 diopter(D)were recruited.The RCLS was composed of a circular light-emitting diode(LED)light source,surgical microscope,surgical video system,computer and self-programming image analysis software.Scheimpflug imaging measurements(Pentacam HR,Oculus,Wetzlar,Germany)were performed on all subjects to determine the axis and power of corneal astigmatism.Thereafter,the axis of corneal astigmatism was analyzed in real-time and displayed by the RCLS on supine position,and videos were recorded.The MB-Ruler 4.0 software was used to measure the astigmatic axis.The accuracy of the RCLS was compared with the Scheimpflug method.Results:The RCLS was able to display the axis of corneal astigmatism in real-time.The axial deviation of corneal astigmatism between the two methods was 0.63±3.78°when astigmatism was 1.00 to 2.00 D and decreased to 0.06±1.38°when astigmatism was greater than 2.00 D.A linear correlation of astigmatic axis was noted between the two methods:Axis_(RCLS)=1.01×Axis_(Scheimpflug)−1.02(R^(2)=0.998,P<0.001).The Bland-Altman analysis revealed that the RCLS agreed sufficiently well with the Scheimpflug method.Conclusions:The RCLS can accurately analyze and display the axis for corneal astigmatism greater than 1.00 D in real-time.The RCLS simplifies marking procedures and may have potential clinical application to improve the postoperative visual outcomes in surgical correction of corneal astigmatism.
文摘AIM:To investigate the effect of astigmatism and spherical equivalent(SE)correction on contrast sensitivity(CS).METHODS:In this cross-sectional study,103 visually normal subjects aged 18 to 36y with bilateral regular astigmatism in range of 1.00 diopter cylinder(DC)to 4.00 DC and normal best-corrected visual acuity(20/20)were recruited.Binocular CS was assessed by linear sine-wave gratings at 1.5,3,6,12,and 18 cycles per degree(cpd),before correction of astigmatism,after full correction of astigmatism by cylindrical spectacle lenses,and after SE of refractive error.The repeated measures ANOVA and Bonferroni test were used to compare the effects of astigmatism correction on logCS.RESULTS:Totally 39 patients were male and 64 patients were female with the mean age of 28.25±5.38y.The average degree of astigmatism in right and left eye was 2.03±0.83 and 2.10±0.78,respectively.Increases in uncorrected astigmatic power correlated with decreases in the logCS,especially at high spatial frequencies.A statistically significant difference in logCS was found between these three cases:before correction of astigmatism,after SE of refractive error,and after full correction of astigmatism by cylindrical spectacle lenses at all frequencies(P<0.001),except at 18 cpd.At 18 cpd,there was no statistically significant difference between logCS before and after SE of refractive error(P=1.0).Also,there was no statistically significant difference in mean CS between with-the-rule(WTR)and against-the-rule(ATR)astigmatism,before correction of astigmatism,after correction of astigmatism with cylindrical lenses,and after SE of refractive error.CONCLUSION:Binocular astigmatism defocus decreases CS depending on the degree of astigmatism power;correction of this will improve patent’s quality of vision.Although high astigmatism refractive error(more than 2.00 DC)that is fully corrected by cylindrical spectacle lenses doesn’t increase the CS to the maximum value,especially at higher spatial frequencies(12 and 18).Also SE refractive error effects on improving CS in low astigmatism power(less than 2.00 DC),especially at lower spatial frequencies.
基金Supported by Independent Research Foundation of the 305 Hospital of PLA(No.24ZZJJLW-010).
文摘Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the eye.It causes blurred vision at any distance and includes corneal,lenticular,and retinal astigmatism.Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism,for example,a large size surgery incision.The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery.Nowadays,three surgical approaches can be used.By placing a sutureless clear corneal incision on the steep meridian of the cornea,a preoperative corneal astigmatism less than 1.0 D can be corrected.Single or paired peripheral corneal relaxing incisions(PCRIs)provide 1.0-3.0 D corneal astigmatism correction.PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism,if more than 2.0 D,the risk of overcorrection and irregular astigmatism is increased.When toric intraocular lenses(IOLs)are unavailable in markets,PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism.Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism.Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D.These approaches can be used alone or in combination.
基金Supported by the OneSight EssilorLuxottica Foundation.
文摘AIM:To describe the distribution of refractive errors by age and sex among schoolchildren in Soacha,Colombia.METHODS:This was an observational cross-sectional study conducted in five urban public schools in the municipality of Soacha.A total of 1161 school-aged and pre-adolescent children,aged 5-12y were examined during the school year 2021-2022.Examinations included visual acuity and static refraction.Spherical equivalent(SE)was analysed as follows:myopia SE≤-0.50 D and uncorrected visual acuity of 20/25 or worse;high myopia SE≤-6.00 D;hyperopia SE≥+1.00 D(≥7y)or SE≥+2.00 D(5-6y);significant hyperopia SE≥+3.00 D.Astigmatism was defined as a cylinder in at least one eye≥1.00 D(≥7y)or≥1.75 D(5-6y).If at least one eye was ametropic,children were classified according to the refractive error found.RESULTS:Of the 1139 schoolchildren included,50.6%were male,58.8%were aged between 5 and 9y,and 12.1%were already using optical correction.The most common refractive error was astigmatism(31.1%),followed by myopia(20.8%)and hyperopia(13.1%).There was no significant relationship between refractive error and sex.There was a significant increase in astigmatism(P<0.001)and myopia(P<0.0001)with age.CONCLUSION:Astigmatism is the most common refractive error in children in an urban area of Colombia.Emmetropia decreased and myopia increased with age.
